/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using Spring.Expressions;

namespace Spring.Validation;

/// <summary>
/// Base class that defines common properties for all validators.
/// </summary>
/// <remarks>
/// <p>
/// Custom validators should always extend this class instead of
/// simply implementing <see cref="IValidator"/> interface, in
/// order to inherit common validator functionality.
/// </p>
/// </remarks>
/// <author>Aleksandar Seovic</author>
/// <author>Erich Eichinger</author>
public abstract class BaseValidator : IValidator
{
    private IList<IValidationAction> actions = new List<IValidationAction>();

    private IExpression when;

    /// <summary>
    /// Creates a new instance of the <see cref="BaseValidator"/> class.
    /// </summary>
    public BaseValidator()
    {
    }

    /// <summary>
    /// Creates a new instance of the <see cref="BaseValidator"/> class.
    /// </summary>
    /// <param name="when">The expression that determines if this validator should be evaluated.</param>
    public BaseValidator(string when)
        : this((when != null ? Expression.Parse(when) : null))
    {
    }

    /// <summary>
    /// Creates a new instance of the <see cref="BaseValidator"/> class.
    /// </summary>
    /// <param name="when">The expression that determines if this validator should be evaluated.</param>
    public BaseValidator(IExpression when)
    {
        this.when = when;
    }

    /// <summary>
    /// Gets or sets the expression that determines if this validator should be evaluated.
    /// </summary>
    /// <value>The expression that determines if this validator should be evaluated.</value>
    public IExpression When
    {
        get { return when; }
        set { when = value; }
    }

    /// <summary>
    /// Gets or sets the validation actions.
    /// </summary>
    /// <value>The actions that should be executed after validation.</value>
    public IList<IValidationAction> Actions
    {
        get { return actions; }
        set { actions = value; }
    }

    /// <summary>
    /// Validates the specified object.
    /// </summary>
    /// <param name="validationContext">The object to validate.</param>
    /// <param name="errors"><see cref="ValidationErrors"/> instance to add error messages to.</param>
    /// <returns><c>True</c> if validation was successful, <c>False</c> otherwise.</returns>
    public bool Validate(object validationContext, IValidationErrors errors)
    {
        return Validate(validationContext, null, errors);
    }

    /// <summary>
    /// Validates the specified object.
    /// </summary>
    /// <param name="validationContext">The object to validate.</param>
    /// <param name="contextParams">Additional context parameters.</param>
    /// <param name="errors"><see cref="ValidationErrors"/> instance to add error messages to.</param>
    /// <returns><c>True</c> if validation was successful, <c>False</c> otherwise.</returns>
    public abstract bool Validate(object validationContext, IDictionary<string, object> contextParams, IValidationErrors errors);

    /// <summary>
    /// Evaluates when expression.
    /// </summary>
    /// <param name="rootContext">Root context to use for expression evaluation.</param>
    /// <param name="contextParams">Additional context parameters.</param>
    /// <returns><c>True</c> if the condition is true, <c>False</c> otherwise.</returns>
    protected bool EvaluateWhen(object rootContext, IDictionary<string, object> contextParams)
    {
        if (When == null)
        {
            return true;
        }

        return Convert.ToBoolean(When.GetValue(rootContext, contextParams));
    }

    /// <summary>
    /// Processes the error messages.
    /// </summary>
    /// <param name="isValid">Whether validator is valid or not.</param>
    /// <param name="validationContext">Validation context.</param>
    /// <param name="contextParams">Additional context parameters.</param>
    /// <param name="errors">Validation errors container.</param>
    protected void ProcessActions(bool isValid, object validationContext, IDictionary<string, object> contextParams, IValidationErrors errors)
    {
        if (actions != null && actions.Count > 0)
        {
            foreach (IValidationAction action in actions)
            {
                action.Execute(isValid, validationContext, contextParams, errors);
            }
        }
    }
}
